The use of Co-Cr
alloys is traditionally carried out by casting, but
it can also be done by using the CAD/CAM system. An
alternative is the use of the laser sintering
technique. By means of a laser, using a
well-established energy/local surface unit, the fine
alloy powder used is locally sintered in order to
form the prosthetic element. The ST2724G alloy used
consists of 64-67% Co, 28-30% Cr and 5-6% Mo, and
has the balance of a γ monophasic structure.
Mechanically, the breaking limits of the metalo-ceramic
elements resulting from this technique are
comparable to metalo-ceramic elements obtained by
classical casting. The metallographic observations
show a slight porosity in the horizontal sample
(compared to the sintering plane), while in vertical
sample, the pore lines are uninterrupted. The
chemical attack shows, just like on the surface, a
very fine layered structure roughly corresponding to
the original granular structure of the base powder.
Punctual analysis shows a high regularity of the
local chemical composition. The laser sintering
technique makes possible the manufacture of
extremely accurate prosthetic elements with
mechanical properties that correspond to any
clinical requirement.
Key words: laser sintering,
ST2724G alloy